Yarn with even shrinkage



.has an unusual result Patented July 11, 1933 PATENT OFFICE RICHARD ELSSNER, OF ELIZABETHTON,

GLANZSTOFF CORPORATION, OF NEW YORK, N. Y.,

TENNESSEE, ASSIGNOR 'IO AMERICAN A CORPORATION OF DELAWARE YARN WITH EVEN SHRINKAGE No Drawing. Original application filed July 2, 1931,

filed October 6, 1932.

My present application is a division of my copending application, Serial Number M8379, filed July 2, 1931.

The invention has to do with a novel method for preventing the uneven shrinkage of artificial filaments.

More particularly, my invention has to do with the prevention of uneven shrinkage occasioned by drying cakes of artificial filaments produced by the pot spinning or centrifugal process.

In the pot spinning or centrifugal method for producing artificial filaments, a cellulosic solution is made up and extruded by pressure through fine orifices into a setting medium from whence it is carried over guiding means to a rapidly revolving receptacle which collects and twists the groups of filaments which are led thereinto. This receptacle or pot throws the filaments against its sides and thus builds up a cake of filaments which, when a suflicient number of filaments has been bunched, is removed therefrom. These cakes are then washed, dried, and otherwise treated. As a result of these treatments the filaments are no longer tightly caked but are comparatively loosely wound. The cakes may be dried either by skcining the cakes or drying the yarn directly in cake form. The drying in the cake form may be done by drying from the inside or from the outside but drying in one direction only, or the yarn is dried from both. sides towards the middle of the cake. If the yarn is dried from the outside towards the center the outer lying filaments tend to shrink before the inner filaments and thus an uneven shrinkage of the yarn in the cake results. Similarly, if the yarn is dried from the inside toward the outside an uneven shrinkage results. I have discovered a method whereby this uneven shrinking may be overcome.

According to my new method the cakes are taken from the centrifugal pot, washed, or otherwise treated, and then dried, for eX- ample, from the outer to the inner side. The cake is then rewet, and dried now from the inner to the outer side. This double drying because it has been Serial No. 548,479. Divided and this application Serial No. 636,585.

found that the filaments first shrink from the outside to the inside thus partially shrinking the middle filaments, and then shrink from the inside to the outside thereby completing the shrinking of the middle filaments and equalizing the shrinking. of both the outer and inner sides. This two step drying, wetting, and drying process results in a cake of filaments which is thor-.

oughly dried and which possesses even shrinkage.

One means whereby the double drying may be accomplished may be described as follows. The cake of yarn is removed from the spinning pot, and the outside surface thereof covered with a water and air tight covering. This cake is then subjected to a drying from the inner to the outer layer of filaments. Then the outer cover is removed; the cake is wet with water; and the water and air tight cover placed about the inner surface of the cake. The drying is then re-' peated this time from the'outer to the inner layer of filaments.

As an alternative method, I have found it feasible to dry, for example, from the inner to the outer side, reverse the loose cake of filaments, and dry again in the same direction. In this way, the cake of filaments, which resembles a doughnut or thick skein, for example, is reversed, i. e., the cake is turned inside out. in a similar manner toturning a bag inside-out, so that the filaments formerly on the outer side are later on the inner side.

It should be understood that when the outor layer is covered as set out above, the top and bottom surfaces of the cake may be similarly protected by flaps extending from this cover.

Having now fully set forth my new invention as required by the patent statutes, what I desire to claim is:

1. In the process of treating hollow cakes of artificial filaments produced from cellulosic solutions, the steps of drying the hollow cake from the inner to the outer side, turning the hollow cake inside out and continuing the drying from the inner to the outer side.

2. In the process of treating hollow cakes of artificial filaments prepared from celluside as the first drying wet cakes from their hollow portions toward their outer peripheries, turning the hollow cakes inside out to present the filaments formerly adjacent the hollow portions on the outer periphery of the cake, rewetting the cake and continuing the drying as before.

In witness whereof I afiix my signature.

RICHARD ELSSN ER. 

